Which of the following statements is false?

a. A class’s private helper methods may be called only by the class’s other methods
b. You cannot declare helper methods in interfaces.
c. An interface’s private instance methods can be called directly (i.e., without an object reference) only by the interface’s
other instance methods.
d. An interface’s private static methods can be called by any of the interface’s instance or static methods.

b. You cannot declare helper methods in interfaces.